2003 年 16 巻 2 号 p. 88-92
Levovist has a significant echo-enhancing effect in patients with an inadequate bone window. We evaluated its diagnostic value in transcranial Doppler sonography (TCD), including its ability to assess hemodynamic parameters of intracranial arteries. The 12 studied patients (5 women and 7 men, ranging in age from 62 to 78 y) comprised 7 with intracranial aneurysms (5 non-ruptured, 2 ruptured), 3 with cerebral infarction, 1 with cerebral hematoma and 1 with brain trauma. According to the precontrast imaging quality, patients were assigned to one of two groups: group 1, highly insufficient native Doppler signal on TCD examination (n=7); group 2, satisfactory waveforms detected on TCD (n=4). Levovist was administered intravenously at a concentration of 300 mg/ml with a total dose of 2 ml (administered in 12 s) or 5 ml (in 30 s). Levovist-induced enhancement characteristics of the Doppler frequency spectrum were then analyzed.
In group 1, Levovist improved the diagnostic utility of TCD, and increases of Vs, Vm and Vd after a 2-ml bolus injection were 7.4±1.6%, 9.4±1.5% and 13.8±2.6%, respectively. After a 5-ml bolus injection the increases of Vs, Vm and Vd were 12.7±2.1%, 13.8±1.7% and 16.1±1.9%, respectively. Either a 2- or 5-ml bolus injection revealed a significant increase of velocity (p<0.05). In group 2, use of the echo-enhancement agent did not influence the Doppler velocity. The mean duration of clinically useful signal enhancement with a 5-ml bolus injection (250 to 395 s, mean 301 s) was significantly higher than that with a 2-ml bolus injection (120 to 250 s, mean 188 s) (p<0.05).
These results indicate that a significant enhancement of flow velocity after Levovist injection was found only in patients with an insufficient acoustic bone window, and no significant change in flow velocity on TCD was detected in patients with a sufficient acoustic bone window.